Most packs come in different sizes or have suspensions adjustable to your torso length. The most important thing is to match your torso length with the size of the pack.

Torso:

Measure your torso length by bending your head forward so your chin touches your chest. Feel for the most prominent bump at the back of your neck. Now measure from that point down to an imaginary line connecting the tops of your hips around your back. This works best with a partner's help.

Sleek and Smart

The North Face has a promising line of pack designs with the Alteo 50. In use in the hot and humid air and hilly terrain in the midwest I found the pack to be quite comfortable. I never expected the ventilated back panel to work as well as it actually does with mere evaporative cooling. If you turn sideways in a breeze it really feels like air conditioning on the back! The tensioned, ventilated back panel combines the best feature of external frame packs from decades ago with a modern, sleek, and smart internal frame pack. The comfortable fit of panel and waist belt conforms to the natural shape of the back and hips. The compression strap system is quite balanced and versatile and allows me to make the pack look elegant and feel sturdy even with small and compact loads. Basically, it can become anything from a 25 L pack to a 50 L pack, or more with the expandable collar under the removable lid. The external side pockets are not accessible with the pack on. The included rain cover is red, which detracts from the overall professional look of the respectable TNF black and grey colors. The hydration tube port hole is very tight and a little fancy finger work is needed to get the bite valve through (the tube itself is no problem). The front zippered access panel is convenient to get inside but does require too many steps-two strap buckles to unlock plus a fabric fold and the overhanging lid to lift up to be able to pull the zippers fully. The waist belt straps fold and tuck away under the hip belt pockets so they do not dangle. After years of using a slightly uncomfortable, minimally padded ultralight 2 pound pack, the Alteo 50 adds a little extra weight but gives an aging back a whole lot of needed comfort. On my scale the pack weighs 1600 grams/56.4 ounces, the lid itself weighs 130 grams/4.6 ounces, and the rain cover weighs 90 grams/3.2 ounces. Happy Trails!